Transportation operation and management review英文.docx

Transportation operation and management review英文.docx

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Transportationoperationandmanagementreview英文

1、交通拥堵的essential原因

Capacityislowerthandemand

Demand---Causedbysocialandeconomydevelopment

Capacity---Providedbyhighwayinfrastructure、Pooroperationsandmanagementmayreducethecapacity

2、RecurrentandNon-RecurrentCongestion

Recurrentcongestion（demand增加）--occurswhendemandincreasesbeyondtheavailablecapacity.Themorningandafternoonworkcommutes.Trafficflowdeterioratestounstablestop-and-goconditions.

Non-recurrentcongestion（capacity减小）--resultsfromadecreaseincapacity,whilethedemandremainsthesame.Thiskindofcongestionusuallyresultswhenoneormorelanesaretemporarilyblocked.

3、拥堵的评价指标QuantifyingCongestion

Duration–theAmountoftimecongestionaffectsthetravelsystem;

Extent–theNumberofpeopleorvehiclesaffectedbythecongestion,andthegeographicdistributionofthecongestion;

Intensity–theSeverityofcongestion（withmeasuressuchasperson-hoursofdelay,averagespeed,etc.）;

Reliability–theVariationoftheotherthreeelements

4、HighwayOperations定义

─Definition:

theimplementationofpolicies,strategiesandtechnologiestoimprovefreewayperformance.

─Objectives:

minimizecongestion（anditssideeffects）,improvesafety,enhanceoverallmobility,andprovidesupporttootheragenciesduringemergencies.

5、ITS定义

IntelligentTransportationSystem（ITS）improvestransportationsafetyandmobilitythroughtheuseofadvancedinformationandcommunicationstechnologies.

6、ITS系统workflow

Architecture:

Theframeworkthatlogicallyconnectsthesystemelementstomeetrequirements.ForITS,thearchitecturewillintegratetheuserservices,allocatetheirsystemrequirementstophysicalelements,anddefinetheirinterconnections.Earlyresearchandtestsprovideinformationnecessarytodevelopanarchitecture.

Standards:

thearchitecturewillidentifyareaswherestandardsandprotocolsareneeded.Somewillalreadybedefined,otherswillbedevelopedthroughthevoluntarystandards-settingprocess.

7、TrafficParameters

TimeHeadway:

Theelapsedtimebetweenthepassageofanidenticalobservationpointbyconsecutivevehiclesinthetrafficstream.

Volume:

Generallyexpressedintermsofflowrate--Atemporalquantitymeasuredefinedasthenumberofvehiclespassingapointinagivenperiodoftime,usually1hour--Flowrateistheinverseoftheaverageofthetimeheadwaysmeasuredoverthesameperiodsuchthatq=3600/h

q=hourlyflowrate（vehiclesperhour）,h=averagetimeheadway（secondspervehicle）,and3600=numberofsecondsperhour.

Density:

thenumberofvehiclesoccupyingagivenamountofroadwayspace（generallyalane–mile）.

Occupancy:

thepercentoftimethedetectionzoneofadetectorisoccupiedbysomevehicle.

Distanceheadway:

thedistancebetweenidenticalpointsonconsecutivevehiclesinsinglefile.

Demand:

theamountoftrafficvolume（orflowrate）thatoccursonafacilityundersomegivensetoftravelconditions.

Capacity:

Atrafficfacility’sabilitytoaccommodateamovingstreamofpeopleorvehiclesinagiventimeperiod.

Throughput:

Thevehicle–milesoftravelcarriedbyagivenlengthofroadwayforagivenperiodoftime.

SpotSpeed:

Thespeedofanindividualvehicleasitpassesanobservationpointofthetrafficstream.

Timemeanspeed:

Thearithmeticmeanofindividualspotspeedsthatarerecordedforvehiclespassinganobservationpointoveraselectedtimeperiod.

SpaceMeanSpeed:

Theaveragespeedofallvehiclesoveraknownlengthofhighwayataparticulartime.（Harmonicmeanofindividualvehiclespeeds）

8、车头时距Timeheadway

9、如何收集spotspeed

Usingaspeedtrapstation,apairofdetectorsisplacedonalengthofroadway.Speediscalculatedfromthetimeittakesvehiclestotransversethedistancebetweenthestartofthedetectionzonesofthetwodetectors.

Instantaneousspeedsofindividualvehiclescanbedeterminedfromtheslopeofthevehicletracesonaspace–timediagram.

10、Timemeanspeed

Anadequatelysizedsampleofspotspeedsisneededtoensurethatthetimemeanspeedapproximatesthepopulationmeantowithinthedesiredaccuracy（atleast50andpreferably100vehicles）.

11、SpaceMeanSpeed

12、延误的分类

Delaymeasuresareusedforfreewaysandsignalizedintersectionstoevaluatethebenefitsofoperationalimprovementsandtoestimatecost-effectiveness

StoppedDelay:

Thesumofthestoppedtimes.

ApproachDelay:

thetotaltimerequiredtotraversetheapproachsectionunderstudy.Itisequaltotheapproachtimelessthetimerequiredforanunimpededvehicletotravelthroughthesamesectionunderfree-flowconditions.

TimeinQueueDelay:

thesumofstoppedtime,motiontime,andexittime.Itisequivalenttothetotalapproachtimeminusthejoiningtime.

13、Time-SpaceDiagramforDelayMeasures

14、单位换算

1mile=1.61kilometers，1feet=0.3048meters，1mile=5280feet

1mileperhour（mph）=1.47feetpersecond（fps）

15、TrafficSurveillanceandDataDetection为什么重要？

它可以应用于许多方面：

trafficmanagement，rampmetering，signalcontrol，freewaymonitoring，accidentdetection，parkingguidance，trafficguidance

16、各种信息采集技术

Inductiveloop

采集的数据

advantages

weakness

Count

Largeexperiencebase

Installationrequirespavementcut

Speed

Mature,wellunderstood

Improperinstallationdecreasespavementlife

Occupancy

Insensitivetoinclementweather

Wireloopssubjecttostressesoftrafficandtemperature

MicrowaveRadar

TrafficVolume

Typicallyinsensitivetoinclementweatherattherelativelyshortrangesencounteredintrafficmanagementapplication

ContinuouswaveDopplersensorscannotdetectstoppedvehicles

Speed

Directmeasurementofspeed

Occupancy

Multiplelaneoperationavailable

InfraredSensors

Speed

Transmitsmultiplebeamsforaccuratemeasurementofvehicleposition,speedandclass

Operationmaybeaffectedbyfogwhenvisibilityislessthan（约等于）20feetorblowingsnowispresent

Length,

Multiplelaneoperationavailable

Installationandmaintenance,includingperiodiclenscleaning,requirelaneclosure

Vehicleclassification

Multizonepassivesensorsmeasurespeed

Passivesensormayhavereducedvehiclesensitivityinheavyrain

UltrasonicDetector

count

Multiplelaneoperationavailable

Environmentalconditionssuchastemperaturechangeandextremeairturbulencecanaffectperformance

presence

Capableofoverheightvehicledetection

Largepulserepetitionperiodsmaydegradeoccupancymeasurementonfreewayswithvehiclestravelingatmoderatetohighspeeds

LargeJapaneseexperiencebase

VideoImageProcessors

volume

Monitorsmultiplelanesandmultipledetectionzones

Installationandmaintenancerequirelaneclosure

density

Easytoaddandmodifydetectionzones

Performanceaffectedbyinclementweather

incidentdetection

Richarrayofdataavailable

Reliablenighttimesignalactuationrequiresstreetlighting

17、Comparison（Fixedtrafficdetectors）

Volume

Speed

Occupancy

QueueLength

VehicleClass

Others

Loops

✔

✔

✔

○

✔

Magnetics

✔

○

✔

○

✔

Microwave

✔

✔

✔

○

✔

timeheadway

Ultrasonic

✔

○

✔

✔

✘

Congestiontime

Infrared

✔

✔

✔

✔

✔

Video

✔

✔

✔

✔

✔

headway,incident

18、RawData的问题

Fromdifferentsensors（differentformats）,multipletypes（numbers,text,video,image）

Toocomplicatedtobeunderstood

19、数据处理流程

20、DataScreening的主要任务

Identifysuspectorerroneousdatavalues，Identifymissingvalues，Identifyinaccuratedatavalues

21、Howtoidentifysuspectorerroneousdata?

Thresholdvalues，Trafficflowtheory-basedapproach，OtherQualitycheck，Clusteranalysis

22、

（1）Maximumvolumethreshold

Usedtodetectvolumesthatareinfeasiblebasedonexpectedhighwaycapacity.Forexample,17for20secondvolumes,25for30secondvolumes,250for5minvolumes,3000pvphplforanytimeperiodlength

23、

（2）Averageeffectivevehiclelength

Forexample,minimumvehiclelength:

9ft;Maximumvehiclelength:

60ft.

24、（3）Maximumspeed

Empiricalevidencesuggeststhatactualspeedvaluesathighspeedlevelsareoftensuspected（e.g.,greaterthan80mphfor5minutes）

25、（4）Minimumspeed

Empiricalevidencesuggeststhatactualspeedvaluesatlowspeedlevelsaresometimesinaccurate（e.g.,lessthan3mph）

26、Datamissing

Causeofmissingdata

SpatialAttributes

TemporalAttributes

Constructionactivitythatdisruptsthetrafficmonitoringinstallation

Datamissingatasinglelocationorseveralconsecutivelocationsalongacorridor

Datamissingforextendedperiodoftime（i.e.severalmonths）

Failureoftrafficdetectors

Datamissingatasingleorseveralisolatedlocations

Datamissingforshortorlongperiodsoftime（i.e.severalminutestoseveralweeks）

DisruptionofcommunicationsbetweenfieldcontrollersandTMC

Datamissingatasingleorseveralisolatedlocations

Datamissingforshortperiodsoftime（i.e.lessthanseveralminutes）

FailureofTMCordataarchivingsystemfailure

Datamissingatalllocations

Datatypicallymissingforshortperiodsoftime（severalhourstolessthanoneday）

27、DataFusion

28、DataMining

1）Anomalydetection （Outlier/change/deviationdetection）–Theidentificationofunusualdatarecords,thatmightbeinterestingordataerrorsthatrequirefurtherinvestigation.

应用：

BeforeusingGPSdatatopredictbusarrivaltime,weneedidentifythenoisepoints.

2）Associationrulelearning （Dependencymodelling）–Searchesforrelationshipsbetweenvariables.

应用：

Finddependencyandcorrelationamongvariousfactorsinaccidentresearch.Forexample,alcoholdrinkingmayhavedifferentimpactsoncrashrisk,dependingondrivergenderandage

3）Clustering –isthetaskofdiscoveringgroupsandstructur